D. Attié , P. Colas, E. Delagnes, M. Dixit, M. Riallot, Y.-H. Shin, S. Turnbull

1. MicroMEGAS + T2K electronics D. Attié, P. Colas, E. Delagnes, M. Dixit, M. Riallot, Y.-H. Shin, S. Turnbull LCTPC Collaboration Meeting - DESY Astrophysics Detector Workshop – Nice – November 18th, 2008

2. Outline • Introduction, technological choice • LP1 beam tests 2008-2009 • Data taking periods • Monitoring • T2K electronics • Specification • Bulk Micromegas with resistive anodes • Carbon-loaded kapton • Resistive ink • Analysis results • Drift velocity • Spatial resolution • Comparison • New method LCTPC Collaboration Meeting – DESY – September 21, 2009

3. Introduction • Need for ILC: measure 200 track points with a transverse resolution ~ 100 μm • example of track separation with 1 mm x 6 mm pad size:  1,2 × 106 channels of electronics • sz=0 > 250 μm amplification avalanche over one pad • Spatial resolution σxy: • limited by the pad size (s0 ~ width/√12) • charge distribution narrow (RMSavalanche~ 15 μm) Calculation for the ILC-TPC •  1. Decrease the pad size: narrowed strips, pixels • + single electron efficiency • need to identify the electron clusters 55 mm D.C. Arogancia et al., NIMA 602 (2009) 403 1. Pixels • 2. Spread charge over several pads: resistive anode • + reduce number of channels, cost and budget • + protect the electronics • need offline computing • could limit track separation 2. Resistive anode LCTPC Collaboration Meeting – DESY – September 21, 2009

4. Data taking • Installation of Micromegas module + electronics in the LP1 in one hour • Smooth operation • Premixed bottle of Ar/CF4/Iso-C4H10; 97/3/2 (T2K gas) • SiPM cosmic trigger (Saclay contribution) very stable (0.65 Hz) • Three periods of data taking: • November-December 2008: Standard, Resistive Kapton • Cosmic runs: 3 days • Beam runs at B=0T: 10 days • Beam runs at B=1T: 7 days • May-June 2009: Resistive Ink, Resistive Kapton • Beam runs at B=1T: 2.5 days • August 2009: Standard • Laser runs at B=1T: 3 days LCTPC Collaboration Meeting – DESY – September 21, 2009

5. Monitoring history • 1 to 2 days at 45 L/h to reach • operation values: • H2O: 140 ppm • O2: 30 ppm • Water content (ppm): 104 103 102 101 105 104 103 102 101 Resistive MM • Oxygen content (ppm): 10-1 Bonn-GEM +TimePix Laser tests +std MM JGEM+ALTRO JGEM+TDC 10-2 June 09 July 09 August 09 September 09 LCTPC Collaboration Meeting – DESY – September 21, 2009

6. T2K electronics characteristics • frequency tunable from 1 to 100 MHz (most data at 25 MHz) • 12 bit ADC (rms pedestals 4 to 6 channels) • pulser for calibration • AFTER-based electronics (72 channels/chip) from T2K experiment: • low-noise (700 e-) pre-amplifier-shaper • 100 ns to 2 μs tunable peaking time • full wave sampling by SCA • Zero Suppression capability • November 2008: AFTER 06’ • May-June 2009: AFTER 08’ with possibility to by-pass the shaping • Bulk Micromegas detector: 1726 (24x72) pads of ~3x7 mm² LCTPC Collaboration Meeting – DESY – September 21, 2009

7. Bulk Micromegas module fro LP1 • Three panels were successively mounted and tested in the Large Prototype and 1T magnet: • standard anode • resistive anode (Carbon-loaded Kapton) with a resistivity ~ 4-8 MΩ/□ • resistive ink (~1-2 MΩ/□) Nov.-Dec. 2008 May-June 2009 Standard bulk Micromegas module Carbon loaded kapton Micromegas module LCTPC Collaboration Meeting – DESY – September 21, 2009

8. Description of the resistive anodes Resistive Kapton ResistiveInk Resistive Ink Resistive Kapton Glue 1-2 μm Glue 1-2 μm Prepreg Prepreg PCB PCB LCTPC Collaboration Meeting – DESY – September 21, 2009

9. Micromegas + T2K electronics in LP1 LCTPC Collaboration Meeting – DESY – September 21, 2009

10. Data flow • DAQ: • Maximum rate: 14 Hz (Zero Suppression mode) • Triggered by beam (no TLU) • Easy to use (GUI) Back-end electronic (ML405) T2K electronics 1728 channels Optical fibre 1-hour automatic rsync backup TCP/IP via ethenet PC T2K DAQ on Linux ILC_BCKP_01 ILC_DATA_01 500 Go 500 Go ILC_BCKP_02 ILC_DATA_02 500 Go 500 Go Grid Saclay NativeToLCIO (Yun-Ha Shin) Transfert done by K. Dehmelt 1 To LCTPC Collaboration Meeting – DESY – September 21, 2009

11. 5 GeV beam data summary (B=1T) • November-December 2008: AFTER 06’ • May-June 2009: • AFTER 08’ with possibility • to by-pass the shaping Resistive Kapton runnumbers LCTPC Collaboration Meeting – DESY – September 21, 2009

12. Determination of z range • Cosmic run at 25 MHz of sampling frequency  time bin = 40 ns • TPC length = 56.7 cm agreement with survey 190 time bins LCTPC Collaboration Meeting – DESY – September 21, 2009

13. Pad signals: beam data sample • B = 1T • T2K gas • Peaking time: 100 ns • Frequency: 25 MHz • z = 5 cm LCTPC Collaboration Meeting – DESY – September 21, 2009

14. Two-track separation capability • B = 0T • T2K gas • Peaking time: 100 ns • Frequency: 25 MHz • z = 5 cm φ r z LCTPC Collaboration Meeting – DESY – September 21, 2009

15. Drift velocity vs. peaking time • B=1T data • For severalpeaking time settings: 200 ns, 500 ns, 1 µs, 2 µs Resistive Kapton • Edrift = 230 V/cm • VdMagboltz = 76 µm/ns • Edrift = 140 V/cm • VdMagboltz = 59 µm/ns Time bins Time bins Z (cm) Z (cm) LCTPC Collaboration Meeting – DESY – September 21, 2009

16. Spatial resolution • Resolution at z=0: σ0 = 54.8±1.6 μm with 2.7-3.2 mm pads (wpad/55) • Effective number of electrons: Neff = 31.8±1.4 consistent with expectations Resistive Kapton LCTPC Collaboration Meeting – DESY – September 21, 2009

17. Comparison at B=1T, z ~ 5 cm Resistive Kapton ResistiveInk • RUN 310 • vdrift = 230 cm/μs • Vmesh = 380 V • Peaking time: 500 ns • Frequency Sampling: 25 MHz • RUN 549 • Vdrift = 230 cm/μs • Vmesh = 360 V • Peaking time: 500 ns • Frequency Sampling: 25 MHz LCTPC Collaboration Meeting – DESY – September 21, 2009

18. Pad Response Functions, z ~ 5 cm Resistive Kapton ResistiveInk xpad – xtrack (mm) xpad – xtrack (mm) Γ = 7 mm Γ = 11 mm δ = 10 mm δ = 13 mm xpad – xtrack (mm) xpad – xtrack (mm)  σz=5 cm = 68 μm  σz=5cm = 130 μm ! LCTPC Collaboration Meeting – DESY – September 21, 2009

19. 2.2 GeV Momentum Resistive Kapton LCTPC Collaboration Meeting – DESY – September 21, 2009

20. 5T data (2006): new analysis A better way to analyze charge dispersion data: • The original PRF “amplitude” dependent on TPC operational parameters • Develop a standard way not requiring fine tuning • Tested several new ideas with simulated data • Apply and test new algorithm to reanalyze DESY 5 T magnetic field results • Criteria: PRF can be applied consistently and easily over a wide range of TPC operating conditions • Observed resolution function is Gaussian. • New measured resolution is as good or better then obtained previously • A simple fixed window integration works the best! LCTPC Collaboration Meeting – DESY – September 21, 2009

21. 5T data (2006): new analysis Resolution comparison: old method vs. “average (700ns)” • New method: 5663/17669 • Flat 40 µm resolution • independent of z • Old method: 3652/17669 Flat 50 µm resolution • independent of z over 15 cm LCTPC Collaboration Meeting – DESY – September 21, 2009

22. Future plan Resistive technology choice In 2008/2009 with one detector module In 2010 with 7 detector modules. Reduce the electronics FEM FECs LCTPC Collaboration Meeting – DESY – September 21, 2009

23. Conclusions • Two Micromegas with resistive anode have been tested within the EUDET facility using 1T magnet to reduce the transverse diffusion • C-loaded Kapton technology gives better result than resistive ink technology • First analysis results confirm excellent resolution at small distance with the resistive C-loaded Kapton: 55 µm for 3 mm pads • New method (fixed windows integration) analysis very promising • Plans are to test another resistive Kapton with lower resistivity (~1 MΩ/□), then go to 7 modules with integrated electronics in 2010 LCTPC Collaboration Meeting – DESY – September 21, 2009